From: John Stultz <jstultz@google.com>
To: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
"Connor O'Brien" <connoro@google.com>,
John Dias <joaodias@google.com>, Rick Yiu <rickyiu@google.com>,
John Kacur <jkacur@redhat.com>, Qais Yousef <qais.yousef@arm.com>,
Chris Redpath <chris.redpath@arm.com>,
Abhijeet Dharmapurikar <adharmap@quicinc.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
kernel-team@android.com, "J . Avila" <elavila@google.com>
Subject: Re: [PATCH RFC v4 2/3] sched: Avoid placing RT threads on cores handling long softirqs
Date: Mon, 17 Oct 2022 20:59:00 -0700 [thread overview]
Message-ID: <CANDhNCqsVm6OFm1aYoWJbha8EXS433JL3-jg3eFLcmE5wX9NOw@mail.gmail.com> (raw)
In-Reply-To: <CANDhNCoTGNANDnOQ6touhreG_UEn1-N4T4BktWFxpLPSWVfrdA@mail.gmail.com>
On Mon, Oct 17, 2022 at 8:42 PM John Stultz <jstultz@google.com> wrote:
> On Mon, Oct 17, 2022 at 5:40 AM Alexander Gordeev
> <agordeev@linux.ibm.com> wrote:
> > select_task_rq_rt() takes the lock and reads curr already,
> > before calling this funciton. I think there is a way to
> > decompose it in a better way.
>
> Hrm. Suggestions? As select_task_rq_rt() is only one of the callers.
> Trying to pass curr into cpu_busy_with_softirqs() would mean
> cpupri_find_fitness() would need to read the cpu_rq(cpu)->curr for the
> specified cpu and pass that in.
>
> The original patch actually was
>
Whoops I didn't finish my thought there. I was going to say the
original patch did similar to your suggestion, passing the target cpu
curr task value in from select_task_rq_rt().
However it didn't use the cpupri_find_fitness() and duplicated a lot
of similar logic in a way that is not as nice as what the current
version uses. But I'm very much open to suggestions for other ways to
simplify that as you suggest.
thanks
-john
next prev parent reply other threads:[~2022-10-18 3:59 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-03 23:20 [RFC PATCH v4 0/3] Softirq -rt Optimizations John Stultz
2022-10-03 23:20 ` [RFC PATCH v4 1/3] softirq: Add generic accessor to percpu softirq_pending data John Stultz
2022-10-03 23:20 ` [RFC PATCH v4 2/3] sched: Avoid placing RT threads on cores handling long softirqs John Stultz
[not found] ` <20221004013611.1822-1-hdanton@sina.com>
2022-10-04 2:29 ` John Stultz
[not found] ` <20221005002149.1876-1-hdanton@sina.com>
2022-10-05 1:13 ` John Stultz
[not found] ` <20221005060155.1571-1-hdanton@sina.com>
2022-10-10 15:42 ` Qais Yousef
[not found] ` <20221011111846.284-1-hdanton@sina.com>
2022-10-12 14:10 ` Qais Yousef
2022-10-17 12:40 ` [PATCH RFC " Alexander Gordeev
2022-10-18 3:42 ` John Stultz
2022-10-18 3:59 ` John Stultz [this message]
2022-10-18 5:32 ` John Stultz
2022-10-19 9:11 ` Alexander Gordeev
2022-10-19 22:09 ` John Stultz
2022-10-20 0:15 ` Qais Yousef
2022-10-20 12:47 ` Alexander Gordeev
2022-10-22 18:34 ` Joel Fernandes
2022-10-23 7:45 ` Alexander Gordeev
2022-11-15 7:08 ` John Stultz
2022-11-15 12:55 ` Alexander Gordeev
2022-10-19 11:23 ` Qais Yousef
2022-10-22 18:28 ` [RFC PATCH " Joel Fernandes
2022-11-15 21:36 ` John Stultz
2022-10-03 23:20 ` [RFC PATCH v4 3/3] softirq: defer softirq processing to ksoftirqd if CPU is busy with RT John Stultz
2022-10-04 10:45 ` David Laight
2022-10-04 19:19 ` John Stultz
2022-10-10 16:09 ` Qais Yousef
2022-10-17 14:44 ` Qais Yousef
2022-10-18 0:04 ` John Stultz
2022-10-19 11:01 ` Qais Yousef
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